Do I need a tune?

[240sxdominos]

I own a 1990 fastback with a redtop sr swap. My mods are as follows.Frontmount ICWalbro fuel pump3inch turbo back exhaust (RSR)s14 t28300zxtt fuel filtertest pipe

I have always had an idling problem but now it has gotten worse since installing the exhaust. The shop I took it to said that my tps was bad (which it was, it read .005v at idle), so I replaced the tps and it now correctly idles at .45 volts, but the car still idles and runs poorly. So my question is, do you think that I just need to tune for all the upgrades I have made? I have a SAFC2 and plan on getting it dyno tuned soon. Any other ideas would be greatly appreciated. thanks in advance-John

[SpeedRacer1]

With your mods a "tune" (I assume you mean dyno tune) would not be worth it. Tuning shouldnt fix the idle problem it will just get better power overall. You need to figure out why a relatively stock setup is idling poorly. Is your ECU throwing any codes? Is your SAFC2 set properly?

[240sxdominos]

could you give me some ideas about why it might be idling badly? I know I have seen a million "bad idle" threads but maybe there is something more specific you can tell me? Could it be that I need a air/fuel ratio tune? because I am definitely running rich. Another question, would running rich lead to heavy backfiring and poor performance in the upper RPM range? because this is happening and makes me afraid to try to push the car. If my wording doesn't make sense then I apologize, I just had my wisdom teeth removed and the pain killers are making me crazy(in a good way....I love percocet!). thanks. -John

To answer your questions Speedracer1, the SAFC2 is just running the stock Maps, nothing has been modified by it, and I dont know anything about the ECU throwing codes, as I have no way of figuring that out. Thanks for your help.

[SpeedRacer1]

There are many possibilities what is going on with your car. How is timing, is it set properly? How are the spark plugs? Gapped properly, correct plugs? All sensors properly working? Good battery voltage? Vacuum leaks? Vac sources not capped? TPS set right, voltage needs to be very accurate?

You need to learn how to read the ECU error codes. Find the screw and LED light on the ECU, turn the car to the on position, turn the screw counterclockwise. The LED should blink, long flashes are the first digit, short blinks are the second digit. So 1 long flash 2 short flashes would be a twelve. The codes will tell you if a circuit is having an issue and can direct you to look at that area.

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